The invention relates to a device for separating flexible planar material, particularly separating blanks from a staple for clothing parts.
The use of the aerodynamical paradox for separating is known, as for instance in DD-PS No. 72,208, where the prevailing suction is used for lifting the top layer off a staple. The prevailing suction is greatly dependent on the material. Furthermore, the danger exists that one or more of the consecutively cut parts may adhere, so that the needed uniformity of operation cannot be guaranteed. Other devices use adherent carriers as for instance DE-OS No. 1,760,616, a method which is not capable of preventing the adherence of additional blanks. Additionally, smudging of adhering surfaces, needed for only a short time, makes repeated cleansing necessary.
Furthermore, it has been known to use operational elements for separating which are furnished with pins, hooks or card filleting. When card filleting is used as in DD-PS No. 104,272 and SU-PS 603,626, two operational elements, each furnished with outwardly pointing card filleting, are positioned upon the top cut part and then spread, whereby the layer of material may be stretched, gripped and lifted off. U.S. Pat. No. 2,160,437 illustrates an analogous principle where the two operational elements denote a rake shaped form with outwardly bent prongs.
A similar principle of solution is found in DD-PS No. 116,192, DE-OS No. 2,002,750, DE-OS No. 2,407,941 and DE-OS No. 2,611,739, where pinshaped parts prick into the edges of the top blank while rotating in an outwardly direction, or where these elements puncture the top piece with an arcuate pin again towards the respective surface, a method which is supposedly aimed at stretching the part to be separated.
All these solutions, though, do not make certain that consecutive layers will not adhere to the piece to be separated. Therefore DE-OS No. 2,160,437 even mentions an additionally-needed auxiliary for separation. Furthermore, the arcuate puncturing can be used only for comparatively thicker material, to prevent the danger that consecutive pieces might be punctured and lifted along too.
DE-OS No. 2,839,257 discloses that the top piece is pricked by vertical pins and thereafter lifted, which permits the same aforementioned disadvantages of decreased reliability of operation.
According to DD-PS No. 123,732 pins are disposed in a circle and point outwardly. These pins prick into the piece to be separated while the plane of material lying within the pins is subjected to tension. This causes the pins to penetrate deeper into that portion of the blank which is stretched, and the process of separation occurs by lifting thereafter. Due to the fact that only a narrowly limited portion of the top piece is acted upon, the danger also exists here that consecutive pieces might adhere. This may happen despite the complicated structure of this device.
Finally, a method is known where pieces to be separated are gripped along points on their surface. Thus, according to DD-PS No. 108,708 two pins are fastened to a thrust-toggle and cause formation of a fold in the material. This fold is clamped by a consecutive cross-over of the pins, while the pin points outline a coupler curve ending almost horizontally.
The suggestion of an additionally needed impulse of compressed air here also shows that this device is not entirely dependable when separation is expected.
Contrary to the aforementioned device, the device of DE-OS No. 2,401,737 grips with two gripping jaws, with one ending in a triangular point and the other provided with a v-shaped recess fitting onto the first one.
All these known technical solutions are not capable of performing a reliable separation from a staple without the need for additional means to separate additional pieces adhering due to adherent properties. These means require additional expenses and frequently damage to the staple or the shape and position of the separated piece is contemplated.
The objective of the invention is to perform the separation process in such a manner that reliable separation of individual top blanks of a staple occurs without additional means, neither shape nor position being impaired in order to make an automatic process possible and, additional automatic processing of the separated individually severed blanks, if necessary.